No plume, but a firehose of data from NASA moon bombing

Early this morning, NASA's LCROSS mission sent hardware crashing into a crater …

This morning, at a hastily arranged press conference, NASA scientists faced a barrage of questions from a frequently skeptical press corps. The questions, however, did not focus on budget issues or plans for future manned missions; instead, the press was concerned about the apparent absence of any visible ejecta from a crater that the Agency had just created by crashing the LCROSS probe into the Moon. NASA seemed very pleased with the data it has obtained, including detailed spectroscopic data, but the press was reflecting the public's desire for a geyser of debris to rise from the impact site and into the field of view of many of the telescopes that were watching.

Regardless of the public expectations, LCROSS clearly performed as planned. It recently separated from the Centaur stage that helped bring it to lunar orbit, and both of the spacecraft were directed towards the Cabeus crater at the Moon's south pole. The Centaur vehicle went first, creating an impact that could be observed from instruments on LCROSS, which followed it in. Less than four minutes later, LCROSS itself struck the lunar surface. The impacts were observed with a variety of telescopes on Earth and in Earth orbit, although the actual site of the impact was obscured by the Cabeus crater walls.

Clearly, a lot of people were hoping that dropping hardware onto the lunar surface would create a spray of debris that would rise above the crater walls, and be visible to the Earth-based observatories. Unfortuntely, from the perspective of the Earth, LCROSS struck not with a bang, but a whimper, as if it had landed on a comfy pillow. NASA scientists spent a lot of the ensuing press conference trying to explain why this didn't necessarily mean that scientists would be disappointed with the data pouring in from instruments around the globe.

Anthony Colaprete, the scientific lead for LCROSS, showed some of the spectroscopic data obtained by the probe's instruments as they approached the lunar surface. From the UV down to the infrared, a time lapse showed signals dropping as LCROSS entered the shadowed region of the crater, until a sudden blip indicated the Centaur's impact. The spatial resolution of the instrument showed that there was a crater in the neighborhood of 18-20m carved out by the impact.

The woman who coordinated the imaging performed by other observatories, Jennifer Heldmann, described some of the data obtained by a massive network of telescopes that followed the impact, saying, "we have images, we have video, we have graphs with squiggly lines, which scientists love."

The observatories that were able to image the event ranged from Arizona and New Mexico (Apache Point, Magdalena Ridge, and the Vatican Observatory), through California's Mount Wilson and Palomar sites, and included a lot of the best hardware in Hawaii, such as the Keck, Gemini, and Subaru telescopes. Watching from space were the Lunar Reconnaissance Orbiter, which was launched with LCROSS, and the newly refurbished Hubble Space Telescope. A few private satellites that normally do Earth imaging, IKONOS and GeoEye-1, were also redirected to the Moon for the event.

Heldmann showed video from a few observatories that spanned the time of the impact, which decisively revealed nothing—hence all the questioning from the press in attendance. Still, it's possible that imaging processing or specific areas of the spectrum will reveal something, and several of the scientists who spoke were anxious to see what came down from the Hubble, which should have started transmitting its data by the time this article is published. Heldmann also mentioned that the Kitt Peak spectral data indicated ionized sodium, something that Colaprete indicated was picked up by LCROSS as well.

That set off another set of skeptical questions: if scientists had spent the time to pick sodium out of the spectrum, surely they had looked for water? Colaprete tried to explain that sodium vapor is known to be present in the lunar atmosphere, and it creates a distinct spectral line in a clean area of the visible spectrum. Water is typically detected in a crowded area of the IR spectrum, which makes it a lot more challenging to pick out. He simply didn't have time to examine it in detail (in part because he was busy making slides for the press conference), and probably wouldn't discuss it if he had, since detailed analysis of the data would be needed before he'd feel comfortable saying anything conclusive. At the moment, that data was still being shuffled around on thumb drives to everyone who was in place to perform the relevant analysis.

In any case, Colaprete noted that excited sodium ions were an indication that something energetic had happened on the lunar surface, so the absence of a visible plume might simply indicate that the hardware had gone into a slope that forced the plume out sideways, or had impacted on solid rock that limited the amount of material sent upwards.

Overall, the press conference made it clear that the mission worked precisely as planned, in that there's a wealth of observational data to analyze—NASA's Mike Wargo said that scientists are currently just "drinking from the firehose"in order to deal with the volume. The recent findings that suggest the existence of lunar water cycle adds a degree of urgency to the work, but the area struck by LCROSS hasn't seen the sun for as long as two billion years, so there was almost certain to be something interesting lurking there.

"Watching from space were the Lunar Reconnaissance Orbiter, which was launched with LCROSS, and the newly refurbished Hubble Space Telescope. A few private satellites that normally do Earth imaging, IKONOS and GeoEye-1, were also redirected to the Moon for the event. "

"Still, it's possible that imaging processing or specific areas of the spectrum will reveal something, and several of the scientists who spoke were anxious to see what came down from the Hubble, which should have started transmitting its data by the time this article is published."

Originally posted by Devin:Okay, seriously, what's the point? How much money did we just throw at creating a dust cloud? Are there any actually useful bits of knowledge that can be gleaned by tossing a can at the moon?

Yeah, doing spectroscopy (analysis with different types of light) on the dust cloud lets astronomers do a sort of "forensics" on the scene to see just what sort of compounds and materials are hidden away in these dark polar moon craters.

If we want to eventually make use of the energy and resources of the solar system beyond Earth, we need to do this. And we may as well start with our nearest neighbor.

You, sir, are an idiot. The moon rotates once per revolution around the earth. We always see the same side, but the moon is still rotating. When the moon is full, the side facing us is lit. When there is a new moon, the far side of the moon is lit. (notice i did not say dark side of the moon.)

Are there any actually useful bits of knowledge that can be gleaned by tossing a can at the moon?

Are you serious?

Yes, of course there is. Spectroscopy of the created impact crater will allow the determination of the composition of the ground in which the crater was created. This composition may result in determination that the site is suitable for various uses by man.

...

quote:

about 6 hours ago from web# “And what's this thing coming toward me very fast? So big and flat and round,

about 6 hours ago from web# it needs a big wide sounding name like 'Ow', 'Ownge', 'Round', 'Ground'!”

about 6 hours ago from web# “That's it! Ground! Ha! I wonder if it'll be friends with me?”

Originally posted by SgtCupCake:I also just wanted to add that the moon doesn't rotate on its axis like the earth does, which is why we always see the same side of the moon. Thus this side never "sees" the sun.

I think you're confusing spin-orbit coupling with no spin at all. The moon has the former: one side always faces Earth, but ALL of it gets light (except for those deep polar craters at sharp angles to the incoming sunlight, hence the probe).

One hemisphere of the moon is always lit and one half dark (just like day/night on Earth), but there is NOT a perpetual "dark side" -- it rotates!

You, sir, are an idiot. The moon rotates once per revolution around the earth. We always see the same side, but the moon is still rotating. When the moon is full, the side facing us is lit. When there is a new moon, the far side of the moon is lit. (notice i did not say dark side of the moon.)

I see no need for name calling. It is my mistake, I was going completly from memory which unlike you, is subject to error.

Originally posted by nitts:potentially stupid question: Could the hubble be pointed at the moon? Or can it not focus that closely? I would think it could get some pretty clear pictures if so?

The Hubble can point at the Moon and can easily focus on it. In fact I think it *was* used earlier today. It could certainly get clear pictures, but a telescope's resolving power is proportional to its aperture, and the Hubble is small compared to large, Earth-based observatories.

Spin-orbit coupling is, I believe, a term from quantum mechanics. The term more commonly applied to this situation is synchronous orbit/rotation. It is exhibited by many of the Solar System's moons.

I can't believe the data analysis is taking them so long. They should have let *real* scientist do the job. Like, the guys from CSI Las Vegas - they would have identified all subspectra by now, if not right away, and would have shown us a 3D holographic animated model of how the cloud developed over time, at 1000 frames/s. NASA is just a bunch of losers.

Originally posted by Commander_Jameson:Spin-orbit coupling is, I believe, a term from quantum mechanics. The term more commonly applied to this situation is synchronous orbit/rotation. It is exhibited by many of the Solar System's moons.

We usually just say Tidal Locked since thats how synchronous rotation comes about, a synchronous orbit is not quite the same thing

Originally posted by Commander_Jameson:Spin-orbit coupling is, I believe, a term from quantum mechanics. The term more commonly applied to this situation is synchronous orbit/rotation. It is exhibited by many of the Solar System's moons.

You know you've taken too many chemistry courses when...

Anyway, thanks, my mistake. The wiki page for tidal lock covers the subject. Maybe I was thinking "rotation-orbit resonance"? There's so many ways to phrase it...

Are there any actually useful bits of knowledge that can be gleaned by tossing a can at the moon?

Are you serious?

Quite serious in fact. That is why I asked. I was just wondering if there was any tangible reason for this. I'm in the "stop screwing around looking for life on other planets and do something useful". If this is as mathrockbrock stated, then I can see that as useful.

Originally posted by morgenrot:I can't believe the data analysis is taking them so long. They should have let *real* scientist do the job. Like, the guys from CSI Las Vegas - they would have identified all subspectra by now, if not right away, and would have shown us a 3D holographic animated model of how the cloud developed over time, at 1000 frames/s. NASA is just a bunch of losers.

Enhance... Enhance... Enhance...I we had CSI's computers we could easily see the plume crystal clear reflected off the LCROSS's solar panels.

Its too bad that diffraction limits exist in the real world. Of course, diffraction limits also mean nobody is reading our license plates from space... so I guess its a fair trade.

Originally posted by marmot_1:This is the result of movies like Armageddon. "You mean you fired your super laser bombs at teh moon and there were no 'splosions?! FAIL"

I could be wrong but I thought that NASA made some promotional materials (video, statements) that might have led the media to believe a plume would be visible. So yeah, they expected too much, but still I don't think it's all their fault.

-- (as opposed to ++) A second ad-hominem doesn't cancel out the first. Got anything to say about astronomy?

hmmm...maybe... but when it's deserved, it's deserved.

About astronomy... hmmm. I'm just waiting for whatever images and analysis do turn up. If there IS water on the moon, what form would it take? hydrated minerals? or ice? Would it exist in a form and distribution that would be amenable to economic recovery and use?

Originally posted by Devin:Okay, seriously, what's the point? How much money did we just throw at creating a dust cloud? Are there any actually useful bits of knowledge that can be gleaned by tossing a can at the moon?

Before you complain about the cost, you should know that this project was actually very clever recycling of the rocket that was ALREADY being used to launch the Lunar Reconnaissance Orbiter (LRO). Once LRO separated, LCROSS remained behind as an additional small spacecraft that maneuvered the spent upper stage into a wide orbit that eventually allowed them to guide it to an impact on the moon exactly where they wanted. This "extra" mission was done on a shoestring budget, and was known to be a risky proposition, so if it had failed no heads would have rolled. And as others have said, the science questions they're trying to answer are extremely important to future exploration.

These people (I know some of them) know full well the budget climate we all live in, so they're always looking for ways to get more use out of what we're already doing. In fact they did an incredible job, especially given their very clever use of hardware that would have just sailed off into space.